What to look for in membranes for Passivhaus projectsMembranes play an important part in helping to deliver airtightness, which is a fundamental principle of the Passivhaus standard. And whether airtight or vapour permeable, they contribute to the management of moisture within the building fabric, reducing the risk of condensation occurring. Pamela Howat, Senior Technical Advisor at Proctor Group, discusses what to look for in membranes when working on a Passivhaus building.